Machine for sharpening tools



June 10, 1952 o. A. JOHNSON 2,599,639

MACHINE FOR SHARPENING TOOLS JNVENHR.

OLAF A.JOHN$ON June 10, 1952 o. A. JOHNSQN 2,599,639

MACHINE FOR SHARPENING TOOLS Filed Feb. 25, 1951 6 Sheets-Sheet 2 FIG. 2

INVENTOR. OLAF A. JOHNSON ATTORNEY June 10, 1952 O. JOHNSON MACHINE FOR SHARPENING TOOLS 6 Sheets-Sheet 3 Filed Feb. 23, 1951 FIG.

o J M A A. L 0% Y v ATTORNEY June 10, 1952 Filed Feb. 23. 1951 O. A. JOHNSON MACHINE FOR SI-IARPENING TOOLS 6 Sheets-Sheet 4 A T TORNE Y June 10, 1952 JOHNSON 2,599,639

MACHINE FOR SHARPENING TOOLS iled Feb. 23, 1951 6 Sheets-Sheet 5 FIG. I?

A T TORNZY Flow! 1 7 l h H6 I23 I 7 7| |5 H8 76 86 47 INVENTOR.

OLAF A. JOHNSON BY QMAJ W June 10, 1952 o. A. JOHNSON MACHINE FOR SHARPENING TOOLS 6 Sheets-Sheet 6 Filed Feb. 25, 1951 FIG. I5

FIG. I6

INVENTOR. OLAF A. JOHNSON ATTORNEY Patented June 10, 1952 MACHINE FOR SHARPENIN G TOOLS Olaf A. Johnson, Irondequoit, N. Y., assignmto The Gleason Works, Rochester, N. Y., a corporation of New York Application February 23, 1951, Serial No. 212,344

16 Claims. 1

The present invention relates to a machine for sharpeningcutting tools, particularly gear cutting tools. the machine being of the general type disclosed in Patent No. 1,908,476, granted to S. H. Earl on May 9, 1933.

The machine comprises a frame which iQurna-lsthe spindle of an abrasive sharpening wheel, the frame also supporting a swinging head that carries a spindle for the tool that is to be sharpened. The arrangement is such that the head may be swung on the frame to carry the blades of the tool back and forth across the Working face of the rotating sharpening wheel.

According to the present invention a power driven mechanism is provided to automatically index the tool spindle for sharpening successive blades of the tool, and the same rotating assem- 1913 that forms the drive part of this indexing mechanism includes a cam which swings the head on the frame in the desired time relationship with the indexing action. The cam operates a crank that is journaled in the swinging head and is connected to the frame by a link.

The same swinging head and link are utilized in. a mechanism that is provided for dressing the sharpening wheel. To this end a diamond or other suitable dressing element is mounted on the swinging head; and the head is swung, to carry this element across the working face of the wheel, by a crank that is journaled in the frame andis connected to the link. During the tool sharpening operation this crank is held stationary, the head then being swung back and forth by the power driven crank on the head. During the dressing operation the crankon the headis held stationary andthe crank on theframe is moved to swing the head. The head is moved through two different arcs by the respective cranks, and hence the tool beingsharpenedand the dressing element although both carried by the head do not contact the sharpening wheel atthe same time. The novel features referred to in this and the immediately preceding paragraph fulfill the primary objective of the invention which is to provide a simple mechanism for accomplishing the several functions described that is inexpensive to manufacture, and is accurate and dependable in operation.

The invention'also provides a simple, rugged and" inexpensive mechanism for effecting, the wheel dressing operation at a uniform preselected velocity irrespective of the force applied by the operator to the dresser operating lever. To this end the operating lever secured tothe crank thatis journaled in the frame, and the motion of the lever by the operator energizes a spring which moves the crank on the return or dressing stroke thereof. At the end of the spring energizingstroke the lever is engaged and held by a latch, and to effect the wheel dressing the operator releases this latch. The rate of the ensuing dressing stroke is controlled by dash-pot means, and may be. varied as desired by adjustment of a metering valve. Provided that the operator moves the lever far enough to apply the latch, the motion following the next release of the latch will be through the full stroke of the dressing element.

The foregoing and other objects and advantages will become apparent from the following detailed description made in connection with the drawings, of which:

Fig. 1 is a perspective View of the machine;

Fig. 2 is a fragmentary plan view with parts broken away and appearing in section;

Fig. 3 is ajview with some parts shown in elevation and others in vertical section in the planes indicated by line 3-3 of Fig. 2;

Figs. land 5 are detail sections taken as indicated by lines 4-4 and 5-5 respectively of Fig.

Fig. 6 is a; vertical sectional view taken along line B -fi of Figs. 2 and 7 Fig. 7 isa section taken as indicated by line l -10f Fig. 6;

Fig. 8 is a detail elevational view of a cam shown in Figs. 6 and '7, and a related crank;

Fig. 9 is a detail plan section illustrating part of the wheel dressing means;

Fig. 10 is a detailvertical section taken as indicated byline Iii-I 0 of Fig. 9;

Fig. 11 is a fragmentary vertical sectional. view in a plane indicated byline l |-l I of Fig. 6;

Fig. 12 isa wiring diagram of the control means for th-emotor that is shown in Figs. 1, 2, and 6;

Fig. 13 is a detail horizontal sectional view of a lost notion take-up means to insure equal travel of the tool as it oscillates while being sharpened;

Fig. 14 is a vertical sectional view through the abrasive sharpening wheel, indicating the manner in which it is rough-dressed; and,

Figs. 15 and 16 are plan and elevational views of a wheel dressing attachment for mounting on the tool spindle.

As shown in the drawings the machine comprises a frame 20 having a stationary spindle housin 2| in which is journaled a vertical spindie 22 for a cup-shaped abrasive grinding wheel. The active'surface of this wheel is in a horizon- 3 tal plane, its outer and inner edges in this plane being indicated by circles 23 and 25 respectively in Fig. 2. The power means for rotating the spindle is not a part of the present invention and hence is not illustrated.

The tool 25 whose cutting blades are to be sharpened (the tool illustrated being a disc milling cutter of the general type employed in Carlsen application Serial No. 765,291, now Patent No. 2,567,273, granted September 11, 1951, and also the diamond element 26 for dressing the wheel, are carried by a head 2i that is mounted to swing relative to the frame 25 about a vertical axis 28 during the tool sharpening and wheel dressing operations. The head 2'! is carried by an arm 29 upon which it is adjustable about horizontal axis 3| to vary the rake angle to be ground on the tool during sharpening. The arm is arranged to swing about axis 28 as a unit with a post 32, and it is adjustable vertically upon this post. The post itself is journaled in suitable bearings in the frame 20.

The connection of the head 21 to arm 29, shown in Fig. 3, comprises a trunnion 33 secured to the head and journaled within a bore in the arm. A worm 34 is journaled in the arm and meshes with a worm wheel 35 provided on the trunnion. By rotating the squared projecting end 35 of the worm shaft, the worm wheel may be rotated to adjust the head about axis 3 i. It may be locked in adjusted position by a screw 31 in the arm that is threaded to a nut that clamps upon the trunnion.

As shown in Figs. 3 and 4 there is journaled in the arm 29 a worm 35 that is turned by a handwheel 39 to drive a wormwheel i i.

The latter is secured to a shaft that is also journaled in the arm and carries a spur pinion 42 which rolls upon a rack 53 on the post 32. Accordingly the arm 29, and the head 2? that is mounted on it, may be adjusted vertically on the post by turning the handwheel 39. A graduated dial A l movable as a unit with the handwheel enables the operator to make this adjustment accurately. The arm may be secured in any adjusted position by tightening a clamping screw 45 which is threaded into the arm against the post. Flexible sleeves 46 around the post 32 prevent the ingress of foreign material into the post bearings and into the adjusting and locking means that have just been described.

The tool 25 is mounted on a spindle 47 that is journaled on anti-friction bearings 48 within a spindle housing 49 that in turn is journaled in the head 2?, coaxially with the spindle, on antifriction bearings 51. For preventing entrance of foreign matter a seal 52 is disposed between the spindle and a nose ring 53 that is secured to the head. Affixed to the spindle housing is an index housing 54 containing an index mechanism through which a motor 55 mounted on the index housing intermittently turns the tool 25 to bring its cutting edges successively into position to engage the sharpening wheel. The spindle 41, its housing 49, the index housing 54 and the motor 55 may be adjusted as a unit about the spindle axis in the bearings 5! by means of worm 56 and wormwheel segment 57. The segment is afiixed to the spindle housing while the worm is journaled in the head 21, as is best shown in Fig. 3. A graduated knob 58 secured to the shaft of worm 56 enables the operator to turn the worm accurately through small angles to thereby make fine adjustments of the tool 25 about the spindle axis. Such an adjustment determines the amount of stock that will be removed from the blades of the tool during the ensuing sharpening operation. The segment 51 may be locked in any adjusted position by tightening a screw 59 (Figs. 3 and 5) that is threaded to a nut 6| to thereby clamp the segment between the nut and a sleeve 62 through which the screw extends. The nut and sleeve are keyed against rotation within the head 21 by pins 63.

The drive for the indexing mechanism (Figs.

6 and 7) within housing 54 includes a worm 64 on the shaft of motor 55 for driving a worm wheel 65 that is secured to the hub of a face cam 66. This cam is rotatable on anti-friction bearings 61 mounted on a stub shaft 68 that is fixed to the index housing. Around the periphery of the cam 65- is a seal for retaining lubricant in that part of the interior of the housing which contains the worm and wheel 64, 65. Secured to the cam 66 to rotate therewith is the drive disc 69 and pin ll of a Geneva motion. The driven member of this motion is an index plate or disc i2 having radial slots 13 to receive drive pin H. The disc 12 has a flange l4, and slot 15 in the periphery of the disc extend through this flange to provide passages for an arcuate ridge 15 that is formed on the drive disc 69. The arrangement is such that for a portion of each revolution of the disc 59 the pin 1| is engaged in one of the radial slots 13, and thereby is driving the disc 12, and that just before and just after this drive a portion of each revolution the arcuate ridge is engaged in a slot 15 to positively hold the driven disc against rotation. The driven disc is fastened by screws 11 to the inner end of spindle 41, to rotate the latter as a unit therewith.

To accurately lock the tool in the various angular positions to which it is advanced by the Geneva motion, there is provided a lock-up dog 18 that is adapted to wedge into the notches 15 in the driven disc or index plate 12. Thi dog is carried by an arm 19 that is pivoted at 8| to the index housing 52. The arm is urged, clockwise in Fig. '7, by a plunger 82 to wedge the dog into lock-up engagement in whichever notch 15 is brought into alignment with it by the Geneva motion. The plunger 82 is carried by the arm 19 and is backed by a spring 83. The plunger engages a screw 84 which is threaded to the housing 52 and thereby provides a means for releasing the compression of the spring when changing the index plate 12. A roller 85 on the arm [9, arranged to roll on a cam surface 86 that forms the periphery of the Geneva drive disc 69, serves to lift the dog 18 from the notch 15 just before the pin H enters into driving engagement in a notch 13 of index plate 12.

For oscillating the tool head 27 about upright axis 28 during a tool sharpening operation there is provided a crank arm 81 having a roller follower 88 engaged in the slot of the cam member 66. The arm 81 is affixed to a shaft that is journaled in the housing 52 and carries another arm 89 (Figs. 1, 2 and 8) on the outside of the housing. As shown in Fig. 8 the groove of cam 65 is so formed that during each revolution it will oscillate the arm 81 twice and then hold it stationary (while the tool is indexed as hereinbefore described). This arm 89 has a ball-andsocket type of universal joint with one end of a link 9| whose opposite end is connected by a similar universal joint to a fitting 92. The last mentioned universal joint has a section that is readily detachable from fitting 92 so that the link may be disconnected easily for a purpose thatwill' be described hereinafter. The link comprises sectionschaving: a screw threaded connectiontoeach other-whereby. its length may be readily adjusted. The fitting 92 is keyed for vertical adjustment upon an upright pin 93 whose ends. are connected by arms 94 to a vertical shaftBS.

The shaft 85 is .iournaled in a bracket 95 that formsa part of the machine frame, and in a tubular post 9.7: on the bracket- Affixed to the end portion of shaft 9.5. within .bracket 96 .is an arm 9.8 (Fig. 9)' which during a tool sharpening operation is held. against an adjustable screw stop: 99: on the bracket. The holding means. comprising. a spring IllrI which abuts a piston I02 whose piston rod 10:8; is connected to the arm fli'liby a pin I04. Thepistonoperates in a..cylinder I115 secured-to bracket .96 .(Figs. 9 audit!) and the spring is. confinedin thecylinder and in a tubular extension thereoitowhich a cap I06. is screw threaded. By adjusting this cap the .compressionof the spring 1111 may. be adjusted.

Inaddition to its .function of holdingthe arm .98 against stop 99. during a tool sharpening operation, the spring IO-I also serves as thermeans for swinging the arm 29 and head .ZEIabout vertical axis 28. during a wheel dressing operation. To enable. the spring to be furthercompressed or: energized for: this. purpose an :operating lever armelfll is afiixed .to..the.,:shaft :85. Whenxthis lever is movedclockwise in Fig. 9., to its limit position-indicated by broken lines, a latch I 08 drops behind it. The latch. is pivoted to the bracket .andisso weighted that itisurgedby gravity. to. its engaged. position, in a counterclockwise direction as it. appears in Fig. 1; Upon release: of the arm: III], by. the .operator moving latch Hi8 clockwise, the springqwill actthrough arm :98 to turn the shaft 85 and .arm .94 (counterclockwise-in Fig. 2 from the broken to the full line position of arms. 94.) and therebyact through thelink :BI to swing the head 2] about'upright -axis:.2.8.:(-also counter-clockwise inFig. 2).

For controlling the rate :at. which the spring .IIlI swings head 21, the cylinder chambers. on opposite sides of. the piston I02 are filled with liquid. and are interconnected by passages I09 and H 1I. between which is interposed screw ad.- justed metering pin 112 .(Fig. 10) which controls the rateof displacement of fluid from the right to the left side of the piston, i. e. in the direction from passage I 09 to passage III. This control is. notcifective during one stroke of the piston 102, when the spring is beingenergized by manual operation of lever I IJ'T, because of .a by.-passage I I3 connecting the passage I09 and III around "the metering pin. This by-passage is closed by a ball check valve II4 when the direction of fluid flow is .from passage I09 to passage III.

For the purpose ofstopping the motor 55- automatically after all the blades of the tool have beensharpened and a subsequent index operation has been completed (i. e. after the lockup dog 18 has become eitective) micro-switches H5 and H6 (Figs. 7 and ,11') are provided, both being secured within the chamber or the index housing to the right of the seal shown in Fig. 6 around cam 66. Switch II5. has a spring-backed actuating. stem II] that engages the outer .end of a pin I I8 that isslidably mounted in the hous ing .52 land isralso backed by a spring. The inner endot-the pinengages-a ring cam I I8 thatis .on'tool spindle 4'1 and is keyedto index plate 12. Cam has a-recess I2.I into which the pin .8

is pressed by its backingspring when the s'pindle is in positioniorsharpening. the first blade of the tool. llhis motionof the pin allows the stem 11:! to shift outwardly, thereby operating a movable contact within the housing of switch .115.

The micro-switch I.I.6 has a. spring-backed actuating stern. I22 that: contacts the face of Geneva. drive disc 69in. the=pathof=an .arcuate cam recess I;23.. The latter is so positioned on disc 69 in relation to cam surface 86; thereof that the stem I22 drops into it under. the urge of itsbackingspringwhenthe dog [8 has. moved into lock-up. engagement with index plate. 12. The stem is cammed inthe. opposite direction, out of the recess I23, just: before the ,dog 18;is swung out of. such lock-up. engagement, mediately preceding the next: indexing operation.

The wiring. diagram, Fig. 12; represents the conditionzof the circuit for thesmotorr55 when the machine is ready to he started; Atxthis. itimethe pin H8. is inthe recessI2I and'the movable con:- tact of the switch :I I5: is closed ZIOIOSSfiXGdxGOIltacts I24' thereof, the otherfixed contacts ofthe switch, whichare. designated .125, being: open. Stem I22 is depressed intoswitch IIGsince in the. positionshownan indexing operation has just been completed and the ,stem' has ridden out of cam. groove 123... In this condition of the switch. 6. its 'movazblecontact :is closed across fixed contacts 126, the other fixed contacts, :I21, of the switch being open.

The control means for the motor: 55. includes a controller IZilthat contains a relay-comprise ing a winding 129. three normally. open. movable contacts I3I which. when closedqconnect. :the motor for forwardoperationto main electrical conductors I132, I33, and I34=of .a three-phase system, and a. normally .openmovable contact I35 which. when. closed: establishes a holding circuit. The unit I128 also contains a; relay comprising a winding I36 and three normally open. movable contacts I31 which. when. closed connect; the motor iorreverse operation to. conductors. I32, I33 and 1134..

The control means also includes relays I38 and I39. Relay I38uhas atwinding. 'I4I, a nor.- mally closed movable contact I42 and a normallyv open movablecontact. I43; Relay 1.3.9 has a movable contact I44, a winding I45; which when energized closes contact: I44, and asw-inding I46; which when energized opens the: contact I 44. Relay I39 is. of atype ;whose.;movab1e cone tact remains in its last. operated position until the relay is subsequently energized.

The control means further includes. a bank I 41 of manually operable switches comprising a push button type of start switch having nor;- mally open movablek contacts I48 and. I49; a normally closed. stopswitch [51; a reversing switch whose movable-contact isnadaptedl'either to close fixed contacts, 1 52" for forward operation of the. motor or to close -fixed contacts il53-f0l' reverse operation; and a switch-I54 which when open allows the motor .to run onlyso long as the start switch is held closed, to provide for jogging, and, when it (switch I54.) is closed, allows the motor to run through its full cycle upon the start switch being closed only momentarily.

A high resistance-signal lamp I55 is provided to show the operatorwhen the tool spindle 47 is positioned for sharpening of the first blade of the tool (when pin H8 is in recessI2i, Fig. 11) and when dog" is in:lock-up position. The circuit for this lamp is from main lead .133 through lead I56, the lamp, lead I5'1,.normally open but now closed contact I43 of relay I38, lead I58, contacts I24 of switch II5, leads I59, I6I and I62, stop switch II, and lead I63 to main lead I32. Contact I43 of relay I38 is closed when contacts I26 of switch I I6 are closed (when pin H8 is in recess I2I, Fig. 11), because the relays winding MI is then energized, the circuit therefor being from main lead I33 through lead I64, winding I4I, leads I65, contacts I26, leads I6I and I62, stop switch i5] and lead I63 to main lead I32.

With lamp I55 lighted, the reversing'switch in forward position and the jog switch in continuous run position, if the start switch button is momentarily depressed, a circuit is established from mainv lead I33 through motor controller forward winding I29, lead I65,forward contacts I52 of the reversing switch, lead I66, start switch contact I48, stop switch I5I and lead I63 to main lead I32. The resulting energization of winding I29 closes motor controller contacts I3I, setting motor 55 in forward operation, and also closes contact I35 which establishes a holding circuit so that the motor will continue to run even though the start switch contact I48 is now opened. This holding circuit provides a shunt around contact.l48, from reversing switch con tacts I52 through jog switch I54, lead I61, contact I35, lead I68, contact I44 of relay I39 and leads I69 and I62'to the stop switch I5I.

This circuit is possible because at this time contact I44 of relay I39 is closed, due to winding I45 of the relay having been energized when start switch contact I49 was momentarily closed. The circuit for energizing winding I45 is from main lead I33 through leads I64 and HI, the winding I45, lead I12, start switch contact I49, leads I13 and I51, contact I43 of relay I38, lead I58, contacts I24 of micro-switch II5, leads I59, I6I and I62, stop switch I5I and lead I63 to main lead I32.

Unless sooner stopped by the operator opening stop' switch I5I (which opens the circuit for controller winding I29) the machine will now run completely through its sharpening cycle. Just prior to the first indexing operation, when dog 18 moves tov unlock index plate 12, the switch IIB will be operated to open its contacts I26 and close its contacts I21. This will provide a shunt circuit (from lead I68 through lead I14, contacts I21 and lead I6I) around contact I44 of relay I39 which is opened by energization of wind ing I46. The circuit for the latter is from main lead I33 through leads I64 and HI, winding I46, lead I15, contact I42 of relay I38, lead I58, contacts I24 of switch II5, leads I59, I6I and I62, stop switch I5I, and lead I63 to main lead I32. Contact I42 of relay I38 is closed at this time because winding I4I has been deenergized by opening of contacts I26 of the switch H6.

As the first indexing operation proceeds, the spindle 41 is turned, moving pin I I8 out of recess I2I (Fig. 11) thereby opening contacts I24 and closing contacts I25. The latter provides a shunt in the holding circuit, via leads I14, I36, contacts I25 and leads I59 and I6I, around the contacts I21 of switch II6 so that when the latter contacts are opened, after the dog 18 has next locked-up, the holding circuit for motor controller winding I29 is maintained.

Contacts I25 remain closed until after the last blade of the tool has been sharpened and the spindle 41 is being indexed to bring the first blade again into sharpening position. At the initiation of the indexing the switch H6 is operated to close contacts I21, which temporarily provides a shunt around contacts I25 of switch Il5, so that machine operation continues even after the latter contacts are opened as an incident to the actual indexing operation during which pin II8 drops into recess I2I. However as soon as the dog 18 has moved to lock-up position the contacts I21 of switch II6 are opened and the motor 1 55 is deenergized. Also the winding I4I of relay I38 is energized, causing the lamp I55 to light, and thereby advising the operator that the sharpening cycle has been completed.

The machine may be jogged forwardly by opening the switch I54. This cuts out the holding circuit for the motor controller and hence the motor 55 will run only so long as the start switch button is held depressed, maintaining thecontact I48 closed. Either forward or reverse jogging may be effected. For reverse the switch is moved to close contacts I53 with the result that whenever start switch contact I49 is closed a circuit is established through the controller winding I36, closing the motor revers contacts I31. The circuit is from main lead I33 through winding I36, lead I11, reverse switch contacts I53, lead I68, start switch contact I48, stop switch I5I, and lead I63 to main lead I32. I

From the foregoing description of the machine it is believed that the operation thereof will be understood. However a typical operating sequence may be briefly summarized as follows: First with the link 9I temporarily disconnected to allow the head 21 to swing freely about axis 28, the dressing element 26 is adjusted in its mounta ing; and then the head is adjusted angularly with respect to arm 29, to the desired sharpening angle. The machine, with link 9I now connected, is jogged forward to move the head to the limit of its counter-clockwise movement about axis 28, as viewed in Fig. 2, this position being indicated to the operator by a pointer on arm 89. The spindle housing 49 is adjusted in the head about the spindle axis to bring the motor 55 to a horizontal position. The tool 25 is mounted on the spindle 41 with one blade thereof in approximately the horizontal plane of the tip of the dressing element 26. Then, with the aid of the handwheel 39, the head is adjusted to bring the dressing element to the wheel. The fitting 92 is adjusted on pin 93 until the link 91 is horizontal and the length of th latter is then adjusted to bring the tool, relative to the wheel, to the full depth to which it is to be sharpened. The machine is then jogged in reverse (with contacts I53 closed) until the lamp I55 lights. Again with the aid of the handwheel 39, the head is raised by whatever small amount of stock is to be dressed off the wheel. The reverse switch is then set to close forward contacts I52. Next the wheel is dressed by moving lever I81 to its-limit position (to the left in Figsl and 2) and by then releasing latch I08. After the ensuing'dressing stroke is completed the start switch button is pressed, whereupon the machine will automatically run through its sharpening cycle as hereinbefore described, the head swinging each blade of the tool twice across the wheel and then indexing to the next blade; and stopping when the first bladehas been indexed to its original position.

The path of the tool and dressing element during the sharpening and dressing operations is best seen from Fig. 2. During sharpening the arms 94 remain in the full line position and the oscillation of the arm 89 from the position shown in Fig. 2 carries the center I18 of its universal joint connection (with link 91:) to. the position shown at I18',swinging the head about axis. 28 to carry the tool to andfr'o'm the broken line position thereof indicated at 25. Thedressing element 26 likewise moves to and: from the: position indicated. at 26', but in doing so remains entirely within the insiderperipheryfl of the wheel and'hence does not contact the wheel. During dressing the point I78 remains fixed relative to head 21., and the latter is swung by oscillation of arm 94 between the full line and broken line positions thereof, which shifts the point I18 toand from the position shown at I18. This moves the dressing element across the face of the wheel, toand from the position thereof shown at 26".

In order to take up all lost motion in the means for oscillating the tool head during a sharpening operation, so that the tool willtravel exactly the same distanceacross the face of the wheel on every stroke of every oscillation, the means shown in Fig. 13 are provided. These include .an arm I19 secured to the lower portion of post .32, and a spring-backed plunger I8I abutting the arm for exerting a clockwise moment (as viewed in plan) about axis 28 on the post, and on the arm 29 and head 21 which swing with the post. The plunger is guided in a bracket I82 that is secured-to the frame 28. The spring-backed plunger thus acts constantly to tension the linkage 92, BI, 89 and to .urge the crank arm fl'lclockwise (in Fig. 8) so that follower roller 88 constantly engages the same surface of the cam 66. In this way any lost motion in. the system is taken upand travel of thetool 25 across the sharpening wheel will repeat accurately on successive rotations of the cam 66.

In Fig. 14 is shown a preferred form abrasive sharpening wheel thatis adapted for usewith the machine of thepresentinvention. It ispreferred to :keep the active face of the wheel narrow in order to prevent burining of the tool that is undergoing sharpening. This narrow face width W of the wheel (the width between the edge circles 23 and .24 of Fig. 2) may be maintained without sacrificing strength of the wheel by periodically rough dressing to a conical surface as indicated'at I83. For performing such dressing the means shown in Figs. and 16 may be employed. This means comprises a dressing element I84 which preferably has a diamond tip and is mounted in holder that has a guide portion I 85 and a handle portion I86. The guide portion is received in a guideway provided in a fixture, comprising a block I81 and a plate I88, held together by screws I89. The fixture may be attached to the forward end of the spindle 47 by a screw threaded fastener I9I at any time when a tool is not mounted on the spindle.

After the fixture has been attached, the spindle 41 may be turned by the adjusting means 58, 56, 51 (Fig. 3) so that the element I84 may dress the wheel to a conical surface I83 of the desired cone angle when the handle I 86 is reciprocated manually by the operator. The head 21 can be raised or lowered by means of the handwheel 39, as hereinbefore described, so that the proper amount of stock can be dressed off of the wheel to bring its active face to the desired width W.

In order to adapt the machine to sharpen tools having a different number of cutting blades, it is only necessary to substitute a different index plate 12 and drive the disc-pin unit 69, II. Such substitution is easily effected since the index housing 52 comprises sections that are separable, upon the line 1-1 of Fig. 6, upon removing the screws that hold them together. Upon such separation 10 both'of the members II and I2 are made accessible. Because of the seal around cam 68 such separation does not. result in loss of lubrieating oil contained in the part of the housing containing the worm and wheel 64, '65.

The foregoing disclosure ismade by wayof example to illustrate and explain the inventive principles involved, and not by way of limitation, there being no intention to limit the scope of the invention except as may be required by the appended claims.

I claim as my invention:

1. A machine for sharpening. gear cutting tools and the like comprising a frame, a Wheel spindle journaled in the frame, a head for supporting-a tool to be sharpened, means for mounting a dressing element on said head, the head being mounted to move on the frame for carrying the tool and the dressing element across the active face of a Wheel on the wheel spindle, a member connected to both the head and the frame, means on the head for shifting the head relative to said member to thereby move the head for carrying the tool across said face of the wheel, and means carried by the frame for shifting said member rela tive thereto to thereby move thehead for carrying the dressing element acros said face of the wheel.

2. A machine as characterized by claim 1 in which the head is mounted to swing on the frame, and the motions of the head effected by the means on the head and the means carried by the frame are swinging motions.

3. A machine for sharpening cutting tools comprising a frame, a wheel spindle journaled'in the frame, a head for supporting a tool to be sharpened, means for mounting a dressing element on said head, the head being mounted to swing on the frame for carrying the tool and the dressing element across the active face i of a sharpening wheel on the spindle, a first crank journaled in the head, a second crank journaled in the frame, a link connecting said cranks, means carried by the head for operating the first crank to swing the head for carrying the tool across said face of the wheel, and means carried by the frame for operating the second crank to swing the head for carrying the dressing element across said face of the wheel.

4. A machine as characterized by claim 3 in which each of the means for operating the cranks is arranged to hold its crank stationary while the other crank is being operated.

5. A machine as characterized by claim 3 in which the means for operating the second crank comprises a spring, dash-pot means for controlling the velocity at which the spring operates the second crank, and a latch for holding the sec and crank cocked for operation by the spring.

6. A machine as characterized by claim 3 in which the means for operating the first crank comprises a drive member journaled for continuous rotation in the head, a cam on said drive member, and a cam follower on the first crank.

'7. A machine as characterized by claim 6 in which a resilient means is provided to constantly urge Swinging motion of the head in one direction to thereby hold the cam follower constantly against one face of the cam.

8. A machine as characterized by claim 6. in which there is a tool spindle journaled in the head for supporting the tool, and a mechanism for indexing the tool spindle intermittently in time with operation of said first crank, said mechanism including a drive element carried by the wheel, said last-mentioned the rotatable drive member and a driven element secured to the tool spindle.

9. A machine as characterized by claim 8 in which the driven element comprises a notched index plate, a plunger is carried by the head for locking engagement in the notches of the plate, and a cam is provided on the drive member for effecting operation of the plunger in time with the intermittent motion of the driven element.

10. A machine for sharpening cutting tools comprising a frame, a wheel spindle journaled in the frame, a tool head having a tool spindle journaled therein, means for mounting a dressing element on the head, the head being mounted to swing on the base for carrying a tool on the tool spindle and the dressing element across the active face of a sharpening wheel on the wheel spindle, an intermittent indexing mechanism including a continuously rotatable drive member journaled in the head and an intermittently rotated driven member secured to the tool spindle, a cam on the drive member, a first crank journaled in the head and arranged to be rocked by the cam, a second crank journaled in the frame, a link connecting said cranks for causing the head to swing, to carry the tool across said face of the wheel, when the drive member rotates, and means for swinging the second crank for also acting through the link to swing the head for carrying the dressing element across said face of means being arranged to hold the second crank stationary while the first crank is being rocked.

11. A machine as characterized by claim 10 in which the means for swinging the second crank and for holding it stationary while the first crank is being rocked comprises a spring, and in which there are dash-pot means for controlling the velocity at which the spring swings the second crank and a latch for holding the second crank cocked for operation by the spring.

12. A machine for sharpening gear cutting tools comprising a frame, a wheel spindle journaled in the frame, a head for supporting a dressing element, the head being mounted to swing on the frame for carrying the dressing element across the face of a sharpening wheel on the spindle, a crank journaled in the frame, a link connecting the crank and the head whereby when the crank is turned the head is swung, a spring connected between the frame and the crank for turning the latter, dash-pot means for controlling the velocity at which the spring operates the crank, an arm on the crank by which the latter may be turned to energize the spring, and a manually releasable latch for engaging the arm to'hold it in the position thereof wherein the spring is energized.

13. A machine for sharpening gear cutting tools comprising a frame, a wheel spindle journaled in the frame, a head for supporting a dressing element, the head being mountedto swing on the frame for carrying the dressing element across the face of a wheel on the spindle, a spring arranged to act between the frame and the head,

for swinging the latter, an operating arm pivoted to the frame and connected to the head forswinging the latter to energize the spring, and a latch for holding the arm in the position thereof wherein the spring is energized.

14. A machine for sharpening gear cutting tools comprising a frame, a wheel spindle journaled in the frame, a tool head having a tool spindle journaled therein, the head being mounted to swing on the base, an intermittent indexing mechanism including a continuously rotatable driven member journaled in the head and an intermittently driven member secured upon the tool spindle for rotation therewith, a cam on the drive member, and a follower of the cam arranged to cause the head to swing on the base, between intermittent rotational motions of the driven member, for carrying a tool on the tool spindle across the active face of a wheel on the wheel spindle.

15. A machine as characterized by claim 14 in which the driven member comprises a notched index plate, a plunger is carried by the head for locking engagement in the notches of the plate, and a cam is provided on the drive member for effecting operation of the plunger in time with the intermittent motion of the driven member.

16. A machine as characterized by claim 3 in which a resilient means is provided to constantly urge swinging motion of the head in one direction.

OLAF A. JOHNSON.

No references cited. 

